Automatic control for water gas plants or the like



J. DANIELS July 9, 1940.

AUTOMATIC CONTROL FOR WATER GAS PLANTS 0R THE LIKE Filed March l18, 19386 Sheets-Sheet l Jce/We p/f Operao'qy Process Q .m QMWSWMQ Qwsmmwm nValves:

.I. Si- S STSSQQ SSQ Purgi'ng n w w, n ha 0 J. DANIELS 2,207,580

-AUTOMATIC CONTROL FOR WATER GAS PLANTS OR THE LIKE July 9, 1940.-

Filed March 18, 1938 6 Sheets-Sheet '2 l AUTOMATIC CONTROL FOR WATER GASPLANTS 0R THE LIKE J. DANIELS July 9, 1940.

6 Sheets-Sheei 5 Filed March 18, 1938 be/a w @ra/e J. DANIELS July 9,1940.

AUTOMATIC CONTROL AFOR WATER GAS PLANTS OR THE LIKE Filed March 18, 19386 Sheets-Sheet 4 valve above be/ow @ra/e J. DANIELS July 9, 1940.

AUTOMATIC coNTRoL FOR WATER GAS PLANTS on THE LIKE v s sheets-sheet 5Filed March 18, 1938 J0 vena E m am July 9, 1940. J. DAN|ELS 2,207,580

AUTOMATIC CONTROL FOR wATE'R GAs PLANTS oR THE LIKE Filed March 18, 1938s sheets-Sheet e IN VENT OR. mrs/664,

Patented July 9, 1940 AUTOMATIC CONTROL FCRv WATER 'GAS PLANTS 0RTHE'LIKE Joseph 'Daniels, Essen, Germany, assignor, by

mesne assignments,A to Koppers Company, Pittsburgh, ya., a corporationAof Delaware Application March 18, 1938, Serial No. 196,796

In Germany March 19, 1937 4 claims.l (o1. 3034-6) The present inventionrelates to automatic controls for shut-off `valves or other closingmeans` of watergas plants, blast-furnace hot blast stoves, or otherinstances inA whichl a series of means is to be moved, for instancevalves are to be opened or closed at a predetermined. sequence byhydraulic contrivances or devices operated by-A compressed-air orothermeans. y

My invention now `comprehends iii-particular those controls for theshut-off valves of intermittently' operated water gas plants. In thefollow'- ing, I shall explain my presentl invention with specialreference toI this working eldand give a more detailed descriptionwithout, however, limiting my invention in all its aspects to use forwater gasv plants'. y

It is known to produce water `gasin 'such a manner that a fuel chargedinto 'a suitablegas producer is heated to a high temperature by burninga part of the fuel with air, whereupon the air supply is stopped andsteam is passed through the glowing fuel. The steam reacts with thecarbon at a high temperature with the format-ion'of a gaseous mixtureconsisting of hydrogemcarbon monoxide and carbon dioxide, said mixturebeing the so-called water gas. As soon as the fuelis cooled-,down by theendothermic water gas `reaction, the supply of steam is' interrupted and'air is introduced again through the fuel in order to heat it up. f

For the production of ywater gas,` it' is often usual to employ a gasproducer consisting essentially of a shaft furnace, which isconnectedfwith the various pipe lines for the air required lfor blowingthe fuel bed hot, for thesteam, and for the water gas, and with thechimney through which escapes the'combustion gases developed during theblow-up period.

Each; of these pipe lines lscontrolled by a shutofiy valve or anothersuitable closing means in such a manner that the respectivepipe lines''are `opened or closed at a given time. Often,` it is usual to make useof hydraulic contrivances for the manipulation of the shut-off valveshorthe like, for example those hydraulicmeans operated by compressed-oil.Manipulatingrdevices operated by compressed-air are also sometimesadopted for the operation of the valves.

As already mentionedv befora the shut-ofi valves cf a water gas planthave to be operated in a given sequence. It is therefore most Aimpor'-tant that each individual valve finishes' rcompletely its movement, i.e., either the openingor closing function before the following. valvelisactuated. Otherwise it may happen that dangerous operating difficultiesoccur. If for iinstancefthev air-valve is still somewhat opened so thatair can enter the gas producer, While `water gas is generated in it bythe introduction of steam, a vcertain quantity ofair may enter the watergas so that highly explosive mixtures of air'and gas will result. On theother hand, it is possible that the valuable water gas will escape'through the chimney damper if same is no-t fully closed. l

Quitea number of suggestions have already orcontrolling apparatusanswers fully the above requirements, i.` e., to prevent a movement ofthe shut-off valves as soon as one of them has not reachedy its exactnal position and to avoid simultaneously other disadvantages with regardto the operation of the plant.

The main 'object of my present invention now consistsiin vthe provisionof a control for water gas plants or the like which is able to fulfilrthe following requirements:

1. The controlling equipment enables a definite but variable sequencefor the manipulation of the various shut-off valves.

2. In case of difficulties, especially when any of the `valves'has notreached fully its end position, the' further reversal of the valves isinterrupted automatically at4 once.

The time between the, actuation of the individualshut-off valves may behighly varied.

4. vNo alteration in the sequence or in the operating periods reducesthe safety of the plant against faulty operations, i. e., the action ofthe shut-off means which prevent the further movement of the controllingapparatus in case of mistakes', is fully prevented. f 5. Finally, it ispossible to make alterations kto the position of the individual shut-offmeans by hand any time, without changing the operation of the automaticcontrolling apparatus. v

The former automatic controlling apparatus vfor water gas plantsgenerally consisted of a control similar to a reversing clock which at agiven' time and at a given sequence manipulated I have already describedin my application forl Letters Patent dealing with Improvements inoperating devices for water gas plants, blast furnace stoves or thelike, executed on the 26th of January, 1938, Serial No. 189,241, ledFebruary 7, 1938, a new and improved automatic control for severalshut-off valves, preferably of blast furnace hot blast stoves, thesystem Cowper, orthe like.

The control described by me formerly Works fully automatically. TherebyI use stop or blocking valves which are operated by the shut-oif valvesafter reaching a given end position, I f one of these shut-olf valvesdoes not come into its proper end position, the movement of theremaining valves is prevented at once. 'Ihe automatic control asdescribed in my former patent application is especially suitable forCowper stoves or similar plants in which the valves do not have to bereversed so often and in which, except one valve governing the deliveryof purging steam, all other valves are opened or closed only once duringone run,

In certain water gas plants'`7 it is however `necessary to open andclose, within one run, several valves, twice or more as the case may be.Further an adjustable pause has to be made between the opening andclosing of the valves as required by the water gas production.

In order to meet also this requirement and to fulfill all otherconditions already pointed out which are necessary for a propersequential control apparatus for the water gas plants or the like, butto make use of fairly simple reversing processes and means, I now havedeveloped a new and improved automatic control apparatus and describedit fully in the following.

' With the above and other objects of my present invention in view, Iwill now describe in detail `my new invention on the lines of theaccompanying drawings which showin principle a preferred embodiment ofmy invention.

Figure 1 of the drawings illustrates a scheme for the operation of awater gas plant and from this scheme it may be seen clearly whichmovem'entsare to be performed by the Various shut-off yvalves of thewater gas plant during a full operating period or run. Figures 2 to 5show more schematically the construction of a reversing device for awater gas production plant, the shut-off valves of which ,may performthe movements illustrated in Figure 1.

' Fig. 6 is a diagrammatic view of the cam discs like cam disc l; andFig. 7 is a diagrammatic view of a non-return valve.

` The water gas production plant for which the execution of the presentinvention isf fully exemplified below, is equipped with 8 shut-oli`valves in total, that is to say: f

1. The shut-01T valve I necessary for the ai to be blown underneath the.grate of thegas producer, said air being hereinafter called primaryalr;

, 2. The shut-off valve 2' for secondary air which is'introduced intothel upper partof the gas progas producer.

ducer for the purpose of burning there the combustibles of the hot blowgases or in the com bustion channel connected with the gas producer sothat for instance the heat thus produced by secondary combustion of theblow gases may be utilized in a regenerator connected with the gasproducer; n

3. The shut-01T valve 3 for purging with steam which is led, after theblow hot period, for a short period from above through the gas producerand the regenerator in order to prevent a mixing of the blow gases withthe valuable water gas;

4. The shut-01T valve 4 controlling the chimney through which the blowgases haust gases escape;

5. The shut-off valve 5 controlling theoutlet of Water gasl above thecharge of the gas producer;

6. The shut-olf valve 6' governing the steam line which delivers thesteam underneath the grate of the gas producer; i

'7. The shut-off valve 'l' governingthe water gas line coming from thespace underneath th grate of the gas producer and y 8. The shut-offvalve' governing the Hsupply of steam to the regenerator connected withthe The scheme according to Figure 1 represents the position of thevarious shut-off valves duringv a complete working period or cycle. Thearrow v a of Figure 1 indicates the direction in whichqthe chart is tobe read in point of time. The following movements of the valves takeyplace during a whole working period or cycle, reading from right toleft of Figure 1: f

upon the gas producer is then purged with steam. Thereupon for a certainperiod, steam is delivered from below through the charge of the gasproducer (up-run) and after this, steam is admitted from above throughthe charge of the gas producer (down-run). Afterwards, steam fis lagainled for a short time from Vbelow through the The apparatus according tothe present invention, full details of which will be given in thefollowing, permits such movement of theshut'- oir valves that theoperating process of the water gas plant, asillustrated in the scheme ofFigure 1, may be carried through exactly as required without it beingnecessary for the operator ofthe plant to perform any manipulation byhand.

Now the automatic control for water gas plants,

and other ex- .35 First of all, the generator is blown hot, wherebuiltaccording to the present invention will be described by me in fullparticulars with reference vto Figures 2 to 5 of the drawings.

erated by compressed-oil (oil under pressure); by means of a pump (notshown on the drawings for reasons of simplicity) the pressure of saidoil is increased to the pressure necessary for the manipulation of theindividual shut-orf valves.

'Each shut-off valve is provided with a hydraulic arrangement in orderto be able to open and close the valve independently of the other oneswhich practice is' already .usual in other automatic'controls for watergas plants.

Instead of operating the .shut-off valves by means of compressed-oil,other liquids or gases under increased pressure also may be used. Insuch a case, the apparatus shown in principle on the accompanyingdrawingahas to be adapted accordingly in a manner which isknown to thoseskilled .in the art.

When using a liquid for the transfer of pressure, it is advisable toreturn the decompressed medium leaving the working cylinders of theshut-oir valves through a collecting line back again to the pump.

The reversal of the shut-01T Valves is effected by means of a controlshaft I3, rotating in stationary bearings Ia. On the shaft I3 aremounted cam discs which at a given sequence actuate one after the other,the Valves which permit the 'flow of the compressed medium to theworking cylinders of the valves and the withdrawal of this medium fromthe cylinders.

The compressed medium for those operating valves which only perform oneoperating movement, one after the other (opening or closing), isreleased or stopped by means of actuating valves `which are actuated bythe operating valves when they reach their final operative position.

I have already described such an arrangement in full detail in mycopending patent application for Improvements in operating devices forWater gas plants, blast furnace stoves or the like, executed on the 26thof January, 1938, Serial No. 189,241, iiled February 7, 1938.

Contrary to all similar automatic controls known hitherto for Water gasplants, the control vaccording to the present invention is characterisedin that the control cams do not rotate continuously but they stand stillat definite periods ofthe operation. The cam shaft is,vhowever,

' constantly under the influence of its driving arrangement, i. e., alsoduring the standstill, so that the cam shaft begins to turn immediatelyupon the withdrawal of the stop out of action. The stoppage of the camshaft is carried out by means of stops which are actuated only throughthe operating valves when they have reached .their proper finalposition, i. e., when the movement of a valve or valve-group is fullycompleted. Only then, the necessary stops of the control cams arewithdrawn and the hydraulic driving arrangement being under a constantpressure is able to move the cam shaft somewhat up to thel next stop.The peculiarity of this driving method for the main impulse of operationof a water gas plant will be described later.

First of all, a full explanation will be given dealing with the reversalduring a complete Working period or cycle.

The reversing apparatus and shut-ofi" valves of the water gas plant havebeen. illustrated on the drawings in a manner such as when all thereversing valves are closed and the chimney valve 4 has just beensupplied with pressure-oil. The cam disc I Vcontrolling the chimneyValve 4 has opened the valves 3 and 4 and closed the valves 5 and 6 bymeans of the lever The Valves 3, 4,

means of the valves I6 and I'I.

5 and E are yplaced on a common rod. From the main compressed-oildelivery line 1, the oil iows through the line 8 and 9 into the lowercylinder chamber of the chimney Valve 4. The oil from the upper cylinderchamber is pressedv through the line I6, valve 4, line I I into the lineI2 for released oil.

The control shaft I3 is actuated by a ratchet wheel I 4 and a hydraulicpiston drive I5 which in its iinal position is reversed automatically byThe reversal is effected in such a manner that at the end `of theleftwise driving stroke of piston I5, a rod I9 pushed to the leftthrough the stop I8 on the piston rod I5@ so that the lever 2li fittedwith a weight 2Go drops into the opposite position to that shown in Fig.2, thus closing the compressedoil inlet valve I6 and opening the oiloutlet valve I'l. The piston now moves to the right, the ratchet idlingover the teeth on disc I4, and the oil from the cylinder chamber 2| ofthe piston i5 is now withdrawn through the line 22, valve II and line II into the wasteeoil line I2. The piston l5 is constructed as adifferential piston and supplied as well as driven from the left-handside on the drawing with compressed oil which flows from the main line'I through the line 23. At the end of the stroke tothe right lever 20 ispulled off of valves I5 and II to the position shown in Fig. 2, openingvalve I5 and closing valve I'I. Oil now flows through I6 to 22 movingthe piston I5 to the left, The oil to the left flows out through 22'into oil iiowirig to valve IB, being thus displaced from the left handside to the right hand side of piston I5, thereby driving the latter tomore slowly drive I s. A speed-regulating valve 24 permits theadjustment of the piston speed. The engagement on the ratchet wheel I4from the rod of the piston I5 is ensured by setting into operation anangledever 25 after each movement of the piston I5. y l

When the cam disc I has pushed downwards the lever 2 by means of thecams and has adjusted the valves for the chimney-damper Il accordingly,then vthe cam 26 of the disc I abuts against a lower stop 32' on the rodof a stop-piston 2l which is not connected with lever 2 but is in thelifted position. Although the piston I5 is still pressing upon theratchet wheel la? and thus upon the control shaft I3, the control shaftnow stands idle because of 26 abutting its stop as shown in Fig. '7.damper 4 has reached its top position, it reverses a three-way cock 28in such a manner'that the compressedv oil from the lower cylinderchamber of the damper 4 ows through the line El and line 2d into theupper cylinder chamber `oi ythe stop piston 21, The stop piston 2l' isthus pushed downwards and the waste-oil from the lower cylinder chamberoi the stop piston 2l' now flows through the line 3E, valve 3l, line Itand through the `opened waste-oil valve d into the waste-oil line II andl2; The showing oi the valve 3l .for the lower stop of the piston#represents a piston valve such as shown in Fig. 6. The oil pressure ofthe line 30 iniiuences the lower piston surface of this valve and thevalve si is lifted against the tension of spring Slate a small eXm tent.When lifting the valve, suitable ports 3| provided` for the pistonshaft, as shown in Fig. 6 of the drawings, are thereby uncovered throughwhich the oilmay iiow underneath the cone seat,

thus reaching the 131106 Iii. The function of the valve43l at thisperiod, therefore is similar to that of a non-return valve.

When the piston of the chimney I Alli and with it the stop for cam 26.

cam on the cam disc for the chimney valve has been made free, but asecond stop 32 pro- 'vided on the piston rod of valve 2I is also drawndownwards and brought within the range of a cam 33 fitted to the camdisc i. This cam 33 comes, however, into action only later-on. Thecontrol shaft I3 is meanwhile still turnedonwards by means of thedriving arrangement, since the cam disc I is free. The valves for thechimney damper 4 remain in the just described open position, as it isnecessary that the chimney damper be kept open for the blow-run.

On rotating the cam shaft I3, at the conclusion of the blow, the cam 35aof the blow cam disc 34 abuts against the lower stop of the rod of thestop piston 35, thus interrupting again the rotation of the cam shaftI3. When the earn 330. lits against the rod of the stop piston 35,` thevalves 38 and 39 are opened and the valves 40 and 4I are closed by meansof the cam face 36 and the lever 31. The compressed-oil now iiows fromthe main line 'I through the line G2, valve 33, line i3 into the lowercylindrical chamber of the secondary air valve 2'. The oil to bedischarged from the upper cylindrical chamber of this secondary airvalve 2' is pressed through the line (lil, through the piston valveagain acting as a non-return valve, through the line dt, valve 39, linel1 into the waste-oil line I2. If the secondary air valve 2 has reachedits upper position, it opens a valve 49 by the aid of a stop and lever48. Compressed-oil from the line d3 flows then through the line 43 intothe pipe and to the lower cylinder chamber of the mainorprimary-air-valve I. In its upper position, the primary air valve Iopensthe threeway cock 5|. The compressed oil now flows from the pipe 5I]through the line 52 into the upper cylinder chamber of the differentialpiston 53.

Chimney damper, secondary air land primary air valves are now opened, i.e., the blow run has started. It is necessary for the blow-run tomeasure accurately the duration and to let it iinish-off automatically.This function is performed by the differential piston 53.

For this purpose, the rod of the differential piston is equipped with arack 55. AV toothed pinion 55 engages such rack. The pinion is equippedwith a pawl 55 under spring-pressure. The spring-loaded pawl 55 engages,on its part, an inner set of teeth on the worm-wheel 5l and as soon asthe upper cylinder chamber of the differential piston 53 has beensupplied with compressed-oil, the pawl tries to rotate the wormwheel.The worm-wheel 5l is, however, prevented from a quick movement due tothe constant rotation of the Worm 51a at a comparatively low andadjustable number of revolutions. A rotation of the worm-wheel 5'? andthus a downwards moving of the piston 53 only at an adjustable speed isthereby rendered possible.

The drive of the worm 57a together with other stop-worms is donecommonly by a shaft 58 which is connected with the axis of the worm5`l'a by means of the'shaft 58a and the conical wheel gearing 58h. Theshaft 58 is fitted with a ratchet wheel 59 which on its part is operatedby a hydraulic .drive 63 which is designed and operated similarly to thehydraulic drive of the cam shaft I3. The number of revolutions for theshaft is in this case, likewise adjusted by a regulating valve 6I in thecompressed-oil line delivering the medium to the hydraulic drive 60.

The duration "of the blow-run depends on the downward velocity ofthedifferential piston 53. The end of the blow-period comes when thestop 62 on the rod of the differential piston 53 touches a springcontrolled lever 63 which opens a valve 64. The period may also bealtered by adjusting the stop 62. The measure of time may be seen from adial 65 mounted on the rod of the differential piston I53. During thedownward movement of the differential piston 53, the oil from the lowersmaller cylinder chamber which is constantly charged with compressed-oilfrom the fio main line 7, is forced backwards again in this line bythe-downward movement of piston 53.

AAt the end of the blow-period, which was de.- termined` by the stop ofthe lever 63, the compressed oil from the line 52 flows through thevalve 65 and through the line 66 into the upper cylinder chamber of thestop piston 35.' The oil from thelower cylinder chamber of the stoppis-1 ton`35 may escape through the line 51, the piston valve 68 actingas a non-return valve, furthermore through the lines 69, 44, pistonvalve 45, line 43, outlet valve 39 andthe waste oil lines 41 and I2.

yAfter the downward movement of the stop piston 35, the lower stop ofthe piston 35 has released the cam 34a so that the control shaft I3 isturned onwards by its driving arrangement. Similarly, tothe chimney disccam, a second stop iso I0 on the piston rod has also engaged at thedisc303 the range of a cam 1I, due to the downwards movement of thestop-piston 35 by which the movement of the control shaft is againstopped.

The distance a between the upper line of the,

lower and the bottom line of the upper Vpiston rod stop of the piston 35isof such dimension that for instance the cam 34a is not free, does notpass over the top of its stop until the upper piston rod stop It hasalready descended and reached the range or path of movement of thesecond control disc stop 1I. In this way,`any undesired onward movementof the control shaft is avoided until the piston rod has descendedenough for stop 1,0 to clear stop 1I, and thus a faulty operation of theshut-off valves is safely prevented. Y

When the cam il on the blow control disc 34 ts against the piston rodstop 10, then the valve lever 3'I is brought back again into theindicated position. In order to avoid a sticking, the face 36 is furtherprovided with a return-sliding face 12 so as to bringthe roller of thelever 31 back into the original position, should it happen that th leversprings 'I3 are weakening.

Now, the valves 38 and 39 are again closed andA differential piston, theoil is discharged from-the I upper cylinder chamber'of the piston53through the line 52, the three-wayv cock 5I, the line14 into thewaste-oil line I2... The differential piston moves upwards at anincreased speed, since the worm and the worm-wheel 51 do notf havel anyunfavourable .eifect ment.

on the upwards move- When the piston of 'the primary air'valve I'hasrline 44 into the upper cylinder chamber of the secondary air valve 2.The waste-oil from the lower cylinder chamber of the valve I' as well asthe waste oil from the lower cylinder chamber of the valve 2' can nowflow through thev line 5l), the opened valve 49, line 43', line 43, theopened outlet Valve 4I into the waste-oil line 41 and I2.

' AIf the piston of the valve 2 has finished its path,`

` the valve 68 is opened in the lower position of the valve 2'. Thecompressed-oil can then ow from the line 44 and 69 into the line 61 `andhere it is introduced into the lower space of the stoppistonA 35. Thestop piston 35 is again lifted and the oil from the upper cylinderchamber of the stop piston 35 penetrates through the line 66,

through the valve 64 acting as a non-return valve,

1I) has been brought outside the range of the cam 'I' I. The cam shaftI3 can now be turned onwards until the cam 15a on the' other disc 15provided for the purging-run, rests against the piston rod stop of thepiston 16. The stop piston -35 of the blow controlling-disc remains inthis drawn position until the next run is commenced with and the cam 34acomes into operation, whereby the valves necessary for the blow-run areopened.

The same cycle is now similarly repeated at al1 further controldiscs,for the purging process, for the down-run, and for the up-run. Thecontrivances are similar to those just described for the blow-run. v

It must also be mentioned that at the end of the purging-run, i. e.,when the upper stop 11 of the stop piston 16 for the purging controldisc is again out of engagement with the stop 18. The time for holdingopen the Valves for the chimneyvalve is completed. The action of theelevated cam face of the chimney controlling discl I terminates here andby' means of its return-sliding rail 19 it leads the valve lever 2- backagain into the horizontal position.

As already pointed out, the stop piston 21 for the chimney cam disc hasbeen pressed downwards by means of the three-way cock 28 at the chimneydamper 4', i.ve., the piston rod camv 32 has been brought within therange of the control disc cam 33.

After completion of the blowing `and purging period and after thehorizontal position of the lever il by the aid of the return-slidingrail 19 has been arrived at, the cam 33 arrives against the piston rodstop 32, thus preventing the further movement of the cam shaft I3;thereupon the closing lperiod for the chimney damper begins. Thecompressed oil from the main line 1 and the delivery line 8 now flowsthrough the opened valve 5 and through the line I9 into the uppercylinder chamber of the chimney valve 4 and the. waste-oil from thelower cylinder chamber goes through the line 9, the opened valve 6 intothe' line I Ivand into the main waste-oil line I2. If the chimney damper4' has reached its lower position, it opens the valve 3| and thecompressed oil from the line I8 enters the line 30, lifting again thestop piston 21 into the withdrawn position in order to offer the stop 26the necessary Aresistance for the next run and to prevent at a giventime the further movement of the controlling disc I3. The oil to bediscarded from the upper cylinder chamber of the .stop piston 21 flowsthrough the line 29, the opened three-way cock 28 into the waste-oilline I2.

As may be seen from the operating scheme shown in Figure 1 of thedrawings, after' the chimney valve 4 is closed the upper water-gas valve5 and uprun steam valve -6 are openedI and closed, then the downrunwater gas outlet valve 1 and downrun steaml valve 8 are opened andclosed. Following this the up-run is on again for a short period afterthe down-run. This portion of the cycle is carried out with the samecontrivance which is used for the up-run. In order to make use of thesame time-measuring apparatus, an additional contrivance has also beenprovided by means of which the time measuring differential piston 88 isprevented from returning into its original top position so thatwhen thetime measurement is intro'ducedrfor the short uprun, the adjustable stop8| on the piston'rod of the differential measuring piston 88 mayagainoperate the valve lever 82 and thus the valvel within the cycle againafter a short period in order to again lead the compressed-oil throughthe line B4 into the upper cylinder chamber of vthe stop piston 85 andthereby to introduce the 'nal closing process for the valves 5 and.A 6'in the same way as described before for the valves I' and 2.

For the purpose of obtaining a shorter return for the differential timemeasuring piston 88, an adjustable stop 86 has been mounted upon thepiston rod of the differential piston 88 which on the return of thepiston 88 towards its upper po- Sition fits against the stop 81 providedwith a piston. 4The piston of the stop 81 is controlled by the valves 88and 89, the latter being governed by a special cam disc 98. Thecurve-face of the cam vdisc 98 extends over its circumference and inparticular within the angle of rotation, which is arranged in such amanner that after the completion of the time measurement for theY maingas process oil under pressure is added from below through the valves 5and 6 into the rear cylinder* chamber of the piston 81 through the line9i.

n In this way, when the time has been measured for the main steamingprocess andthe diierential piston 88 is to go back into its initial topposition, it is only necessary to touch a part of this return-way untilthe stop 86 actuates the piston rod 81. After completion of the shortup-run, the compressed oil from the line 9I and thus from the rearcylinder chamber of the piston 8.1 is removed again by a suitable guideof the curve face of the controlling cam 98. The front of thedifferential piston 81 is exposed to the influence of compressed-oilwhich may ow over constantly from the line 92 which on its part isconnected Acam discs 93 and 94, as already described in connection withthe controlling cam disc I yand the controlling cam discs for theblowing and purging cycle.

In orderv to be able to manipulate the individ-"75 ual valves by handwhich are equipped with counter-Weights and hand Winches, a three-waycock has been built into the main compressedeoil line 1. In closedposition, the line '1 can be connected with the waste-oil line 'I2through the line 96. Thus, all valves are released vfrom pressure-oil. Aspecial advantage of the before described reversing arrangement consistsin that the valves remain fed with compressed oil even in closedposition, i. e. they are kept in their closing-position. The controllingapparatus is` suitably mounted in a cabinet, whereby the valve levers 2,3letc. are provided with plates showing the inscription of therespective operating process, i. e., blow purgingf steamingf etc. It isadvisable to make the plates visible through the Windows of theapparatus casing. Furthermore, it is possible to fix a sector-plate 98to the head of the controlling shaft. Also the plate 98 is placed behinda glass pane to observe the condition of the reversing apparatus. v

Moreover, the controlling cam device may also be operated by ahand-drive 93 in case of a failure of the hydraulic drive.

ner through the reversing casing; permit the manual operation in orderto be able to manipulate the various valve groups independently,` Forthis reason, also the from one another. stop pistons 27, 35 and 1S `areequipped with handles. It is, of course, understood that some furtherblocking valves and rods will become necessary which are not shown onlthe drawings so that in case of a manual operation. the hydraulic driveof the controlling shaft. I3 as well as the various compressed-oilsupplies 8, etc. connected with the main line 1, may be stopped. The

handles for the manipulation of the valve leversv and the controllingcams must, however, be kep-t covered during the hydraulic drive and thetouching of them by people not on business is prohibited and must berendered impossible for example by suitably designed hoods, bridgingover the handles of the levers and being stopped in such a manner thatthey can only be opened if the main drive is disconnected and all otherarrangements have been made in order to prevent any faulty operation.

The reversing operation must finally also allow to be interrupted duringthe charging period. This may suitably be also done by the main shutoffcock 95 in that it is connected preferably with the starting device ofthe charging operation.-

Summarising, I should like to make the iollowing remarks:

With the apparatus illustrated onI the drawings, the reversal of thevalve groups is effected by controlling cams and the reversal of thevalves within the various groups is done by suitably arrangedend-position-valves which are operated -by the slide-valves at asimultaneous introduc- Aconstantly influenced by its driving device, butit suitably, two hiv-1 draulic drives each are provided for the driveris hindered in its movement by means of stopcams. The stop cams are onlyreleased if certain conditions have been fulfilled in connection withthe next operation. The conditions for the following operation are then'answered if the measuring time for one working process has elapsed andfurthermore if the last valve of anr operating group has again reacheditsl proper final position. Dependent on these two operatingcircumstances, the stop pistons areadjusted which hinder the movement ofthe control shaft The same reversing operation may also be adopted forsimple operations for instance for hot blast stoves, system Cowper orthe like.

The

valves would for instance have tcbe fitted with a controlling discnecessary for the starting-up.

In the claims affixed to this specification nose-` lection of anyparticular modification of my inventionl is intended to the exclusion ofother modifications thereof.

`I claim: l

1.l In apparatus for automatic sequential control, in combination: a setof hydraulic valve` operating'pistons; a set of fluid pressure lines foractuating each of the same; hydraulic pilotpiston valves in therespective sets of lines for controlling the actuation of the valveoperating pistons; a series `of control cams mounted for rotation inunison on a rotatable shaft therefor,r

for the respective `valve operating pistons; a cam follower interposedbetween each of the pilotA valves and their respective cams foractuating the pilot valves; cam stops movable into and out of stoppingengagement with the respective cams for arresting and releasing inunison the movement of the cams; an hydraulic stop-operating pistonindividual to the stops for the individual cams for operating the same;and uid pressure lines and valve means therefor individual to the.

respective stop-operating pistons; and means operableby the respectivevalve operating pistons, intheir end positions, for operating the valvemeans for their respective stop-operating piston to effect reversalA ofmovement of 'their stops relative to their respective cams.

2. An automatic control apparatus as claimed in claim l, and in whicheach of the control cams '55.

is .provided with two stop-engaging members, in staggered position toone another, within the range of the cam stop which is moved into andout of stopping relationship therewith by means of its hydraulic piston,whereby one stop enga,-v

interval after its valve operating piston has been actuated to its openposition.

4. An automatic control as claimed in claim '1,

and in which a shut-olf valve, and an adjustable time-relay hydraulicpiston therefor, are inter-v opened by the time relay piston for iiow ofpressure medium tothe stop-operating piston, and in which the time relayis provided With a Arotatable braking gear acting to control themovement of the time relay piston on its active stroke and to f returnthe latter to its initial position on its idle stroke.

JOSEPH DANIELS.

